Process for producing polyisocyanate and resin composition comprising said polyisocyanate for use in paints

Abstract

A process for producing a polyisocyanate containing an isocyanurate ring which comprises reacting at least one diisocyanate compound selected from the group consisting of alkylene diisocyanates, cycloalkylene diisocyanates and aralkylene diisocyanates with a cycloalkylene diol in the presence of an isocyanurating catalyst; and a resin composition for use in non-yellowing fast-drying urethane paints, comprising (A) the aforesaid polyisocyanate and (B) an acrylic polyol having a number average molecular weight of 2,000 to 30,000 and a hydroxyl value of 20 to 200.

What is claimed is: 
     
       1. A process for producing a polyisocyanate containing an isocyanurate ring which comprises reacting at least one diisocyanate compound selected from the group consisting of alkylene diisocyanates, cycloalkylene diisocyanates and aralkylene diisocyanates with a cycloalkylene diol in the presence of an isocyanurating catalyst. 
     
     
       2. A resin composition for non-yellowing fast-drying urethane paints, said composition comprising as essential ingredients (A) a polyisocyanate containing an isocyanurate ring obtained by reacting at least one diisocyanate compound selected from the group consisting of alkylene diisocyanates, cycloalkylene diisocyanates and aralkylene diisocyanates with a cycloalkylene diol in the presence of an isocyanurating catalyst, and   (B) an acrylic polyol having a number average molecular weight of 2,000 to 30,000 and a hydroxyl value of 20 to 200.   
     
     
       3. The process of claim 1 wherein the diisocyanate compound is a mixture of an alkylene diisocyanate and a cycloalkylene diisocyanate in a weight ratio of 85-55:15-45. 
     
     
       4. The composition of claim 2 wherein the diisocyanate compound is a mixture of an alkylene diisocyanate and a cycloalkylene diisocyanate in a weight ratio of 85-55:15-45. 
     
     
       5. The process of claim 1 wherein the diisocyanate compound is a mixture of an alkylene diisocynate and an aralkylene diisocyanate in a weight ratio 95-70:5-30. 
     
     
       6. The resin composition of claim 2 wherein the diisocyanate compound is a mixture of an alkylene diisocyanate and an aralkylene diisocyanate in a weight ratio of 95-70:5-30. 
     
     
       7. The process of claim 1 wherein the cycloalkylene diol is a diol having 5 to 30 carbon atoms and containing a 5- to 7-membered rigid ring and is used singly or as a mixture of diols in an amount of about 0.3 to about 30 mole % based on the total amount of the diisocyanate compounds. 
     
     
       8. The process of claim 1 wherein aralkylene diisocyanate is present in an amount of not more than 50 mole % based on the total amount of alkylene diisocyanate and/or cycloalkylene diisocyanate. 
     
     
       9. The resin composition of claim 2 wherein the diisocyanate compound contains not more than 50 mole % of aralkylene diisocyanate based on the total amount of alkylene diisocyanate and/or cycloalkylene diisocyanate. 
     
     
       10. The process of claim: 1 wherein the isocyanurating catalyst is a compound having a low electron density and containing a strongly cationic atom or atomic grouping and is selected from the group consisting of compounds of the general formulae ##STR8## wherein R 1 , R 2 , R 3 , R 5 , R 6  and R 7  are identical or different and each represents a C 1  -C 20  hydrocarbon group or C 1  -C 20  hydrocarbon group containing a hetero atom such as nitrogen, oxygen or sulfur; R4 and R 8  represent a hydrogen atom, a C 1  -C 20  hydrocarbon group or a hydroxyl group containing C 1  -C 20  hydrocarbon group; X 1 .sup.⊖  represents a hydroxyl group, a monocarboxylate anion or a monophenolate anion having a C 1  -C 20  hydrocarbon chain; X 2   2 ⊖  represents a dicarboxylate anion or a diphenolate anion having a C 1  -C 20  hydrocarbon chain; R 9  represents a C 1  -C 15  hydrocarbon group or a C 1  -C 15  hydrocarbon group containing a hetero atom and M e  represents sodium or potassium. 
     
     
       11. The process of claim 1 wherein the isocyanurating catalyst is used in an amount of 0.001 to 0.2% by weight based on the total amount of the diisocyanate compound and the diol charged. 
     
     
       12. The process of claim 1 wherein the isocyanurating reaction is carried out at a temperature in the range of about 30° to about 120° C. 
     
     
       13. The process of claim 1 wherein the amount of the polyisocyanate formed is within the range of 20 to 70% by weight based on the total amount of the starting material. 
     
     
       14. The composition of claim 2 wherein the polyisocyanate (A) containing an isocyanurate ring has a molecular weight of 500 to 2,000. 
     
     
       15. The composition of claim 2 wherein the acrylic polyols have a glass transition point (Tg) of from 25° to 80° C. 
     
     
       16. The resin composition of claim 2 wherein the polyisocyanate component (A) and the acrylic polyol component (B) are blended in proportions to provide an equivalent ratio of isocyanate groups and hydroxyl groups, NCO/OH, of 0.3 to 2.0. 
     
     
       17. The resin composition of claim 2 wherein the acrylic polyol is obtained by radical polymerization of at least one ethylenic hydrocarbon selected from the group consisting of styrene, alpha-methyl styrene, p-methyl styrene, p-methoxy styrene, p-tertbutylstyrene, methyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate, ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, 2-ethoxyethyl acrylate, beta-hydroxyethyl methacrylate, beta-hydroxypropyl methacrylate, beta-hydroxyethyl acrylate, diethyl fumarate, di-n-butyl fumarate, diisobutyl fumarate and di-2-ethylhexyl fumarate.